A mobile terminal is a terminal that can be freely used while moving around without positional restrictions. A typical mobile terminal includes a mobile communication terminal such as a cellular phone; a personal digital assistant (PDA) called a personal portable terminal, etc. Accordingly, the term “mobile terminal” used herein includes all of the above-described terminals. In the following description, however, for convenience of explanation, the mobile terminal refers to a PDA.
PDA is referred to as a pocket computer, collectively called a palm-sized compact device with a calculation function and an information storing and searching function for a personal or business use, and is widely used to keep information of a schedule calendar and an address book.
In particular, an industrial PDA is widely used mainly for distribution industry and a market for the industrial PDA is gradually growing. The industrial PDA is equipped with various office functions such as a barcode scanner, a credit card reader, etc., which are not provided in a general PDA. The use of the industrial PDA makes delivery, document management, and related businesses easy and efficient. For example, in an insurance company, an insurance broker can directly process various insurance related businesses such as customer information management, customer search, schedule management, meeting schedule management, anniversaries search, fund statement processing, etc., on the spot by using the industrial PDA. Next, in a hospital, medical staffs can input or search for patient's treatment records and case history, prescriptions, images such as X-ray images, graphical materials, etc., without restrictions in time and place, by using the industrial PDA being carried. Also, for police forces' services, police forces' outside duty such as traffic control or neighborhood security is performed by using the industrial PDA so that a fine issued for a traffic offense can be instantly paid through a financial institution, which could have been paid 2-3 days after the fine was issued. As a result, the police forces' outside duty time can be remarkably reduced.
As it can be seen from the fact that the industrial PDA is used in the above-described various industrial fields, the industrial PDA needs to endure any industrial environment, not a general environment for a general PDA, beyond a certain level. In other words, unlike a general PDA, it is expected that the industrial PDA may be used in a cold storage warehouse below −10 degrees or outdoors for a long time. Also, the industrial PDA may be toughly handled by a user like a postman. Accordingly, an industrial PDA equipped with an anti-shock function, a waterproof function, and anti-heat/cold function, etc. may be competitive in the product market. As such, it is essential that the industrial PDA is manufactured tougher and harder than a general PDA and further equipped with a waterproof function to endure snow or rain.
The industrial PDA has various parts and structures into which foreign materials or moisture may intrude in manufacturing and assembling processes thereof. For example, a structure such as a keypad, a touch window, a trigger, etc. corresponding to a user input device is difficult to be equipped with a waterproof function, and even if it is possible, the structure becomes complicated so that manufacture and assembly thereof is difficult. Also, for an industrial PDA to have a waterproof function, a coupling portion of upper and lower cases and a battery pack require a waterproof process. Thus, in the case of an industrial PDA, development of a product having a structure that is easy to manufacture and assemble and has a superior waterproof function is needed.